1. Field of the Invention
This invention relates to synthesis of hydrogen peroxide from its constituent elements, hydrogen and oxygen, and more particularly to the use of methanol as the medium in which the synthesis takes place.
2. Prior Art
The synthesis of hydrogen peroxide directly from its constituent elements has conventionally been carried out in essentially aqueous solvent systems.
It has been proposed by Hooper, in U.S. Pat. No. 3,361,533, that hydrogen peroxide synthesis using a supported metal catalyst in an aqueous medium containing an acid is enhanced by inclusion of an oxygen-containing organic solvent, such as alcohols, aldehydes, ketones, ethers, ester, amides and oxygen-containing amines in the aqueous medium. The preferred medium is 75:25 acetone:water by volume. However, acetone as the sole reaction medium was said to result in the formation of no peroxide at all. A medium of 75:25 isopropanol:water produced an explosive reaction. It is, therefore, clearly apparent that the nature of the reaction medium profoundly influences the course of the reaction and that significant amounts of water are required for an effective reaction.
In U.S. Pat. No. 3,336,112, Hooper has proposed inclusion of a sequestrative stabilizer in an aqueous medium for direct hydrogen peroxide synthesis from the elements using a supported Group I or Group VIII metal catalyst.
It has been proposed by Campbell in U.S. Pat. No. 3,433,582, that hydrogen peroxide can be synthesized directly from hydrogen and oxygen by contacting a solid catalyst in a liquid medium containing water and dissolved boric acid.
It has further been proposed by Kim et al, in U.S. Pat. No. 4,007,256, that hydrogen peroxide is produced by contacting hydrogen and oxygen with a supported catalyst in the presence of water, an organic nitrogen-containing compound and a strong acid.
It has further been proposed by Izumi et al, in U.S. Pat. No. 4,009,252, that use of an entirely aqueous acid solvent for synthesis of hydrogen peroxide using a palladium catalyst prevents the formation or accumulation of organic peroxides. However, the process requires the use of high hydrogen and oxygen pressures, which can be hazardous, and is limited by the low solubility of hydrogen and oxygen in all-aqueous systems, which results in undesirably low hydrogen peroxide formation. The process is therefore unattractive from a commercial viewpoint.